The term 'allergy drug' can be broken down into four crossword solutions: POLLEN (6 letters), asthma (6 letters), achoo (5 letters), and RASH (4 letters). Allergy drugs are medications used to treat allergic reactions, which are caused by an overreaction of the immune system to a foreign substance. POLLEN is a common allergen that can cause sneezing, watery eyes, and a runny nose. Asthma is a chronic respiratory condition that can be triggered by allergens such as POLLEN, dust, and pet dander. Achoo is an onomatopoeia for sneezing, which is a common symptom of allergies. A RASH is a skin reaction that can be caused by an allergic reaction to a drug or other allergen. Allergy drugs can help reduce the symptoms of these conditions.